PInvokeStackImb alance was detected.

John,

[DllImport("user 32.dll", CharSet=CharSet .Auto, PreserveSig=tru e)]
private static extern IntPtr OpenDesktop(str ing lpszDesktop, int
dwFlags, bool fInherit, long dwDesiredAccess );

^^^^

Should be a (u)int.
Mattias

--
Mattias Sjögren [C# MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

"John Sudds" <John Su***@discussio ns.microsoft.co m> wrote in message
news:98******** *************** ***********@mic rosoft.com...
| The MDA appears on the call to OpenDesktop.
|
| I have tried a variety of approaches (including specifying the A and W
| variant with ExactSpelling=t rue, and PreserveSig=tru e) but none of them
seem
| to work. This code was copied from a 1.1 sample that purported to work
| without an error.
|
|
| public static class Desktop
| {
| private const long DESKTOP_SWITCHD ESKTOP = 0x0100L;
|
| [DllImport("user 32.dll", CharSet=CharSet .Auto, PreserveSig=tru e)]
| private static extern IntPtr OpenDesktop(str ing lpszDesktop, int
| dwFlags, bool fInherit, long dwDesiredAccess );
|
| [DllImport("user 32.dll")]
| private static extern bool SwitchDesktop(I ntPtr hDesktop);
|
| public static bool IsLocked()
| {
| IntPtr hdt = OpenDesktop("De fault", 0, false,
| DESKTOP_SWITCHD ESKTOP);
|
| if (IntPtr.Zero == hdt)
| return false;
|
| return SwitchDesktop(h dt);
| }
| }
|

The last argument is not a long it should be an unsigned int.
The MDA did not exist in v1.1, so that means it's only reported now.

Willy.

THANKS to both of you! My problem was that ACCESS_MASK (the last param of
OpenDesktop) is unsigned.
"John Sudds" wrote:

The MDA appears on the call to OpenDesktop.

I have tried a variety of approaches (including specifying the A and W
variant with ExactSpelling=t rue, and PreserveSig=tru e) but none of them seem
to work. This code was copied from a 1.1 sample that purported to work
without an error.
public static class Desktop
{
private const long DESKTOP_SWITCHD ESKTOP = 0x0100L;

[DllImport("user 32.dll", CharSet=CharSet .Auto, PreserveSig=tru e)]
private static extern IntPtr OpenDesktop(str ing lpszDesktop, int
dwFlags, bool fInherit, long dwDesiredAccess );

[DllImport("user 32.dll")]
private static extern bool SwitchDesktop(I ntPtr hDesktop);

public static bool IsLocked()
{
IntPtr hdt = OpenDesktop("De fault", 0, false,
DESKTOP_SWITCHD ESKTOP);

if (IntPtr.Zero == hdt)
return false;

return SwitchDesktop(h dt);
}
}

For those who are interested in the final rewrite, here it is. This code is
running inside a screen saver, and accurately detects whether the Default
desktop has been locked (before, after, or during).

public static class Desktop
{
private const uint DESKTOP_READOBJ ECTS = 0x0001;
private const uint DESKTOP_WRITEOB JECTS = 0x0080;
private const uint DESKTOP_SWITCHD ESKTOP = 0x0100;
private const uint AccessUnlocked = DESKTOP_READOBJ ECTS |
DESKTOP_WRITEOB JECTS | DESKTOP_SWITCHD ESKTOP;

[DllImport("user 32.dll", CharSet=CharSet .Auto, SetLastError=tr ue)]
private static extern IntPtr OpenDesktop(str ing lpszDesktop, int
dwFlags,
bool fInherit, uint dwDesiredAccess );

[DllImport("user 32.dll")]
private static extern bool SwitchDesktop(I ntPtr hDesktop);

public static bool IsNotLocked()
{
IntPtr hdt = OpenDesktop("De fault", 0, false, AccessUnlocked) ;

// If we can make the switch, the desktop is not locked
if (SwitchDesktop( hdt))
return true;

return false;
}
}